Device for stabilizing and homogenizing liquid mixtures



Tega- 9 w m 4, mgm 3S V.0v. 2,90n 0m,

m www .m NLW mB Eml n@ HZ. f Aml 6 mv. /OJ .Amm .Hm HOd cHe 9 Amm v OJ nZA D B.G.w M Ll .mm 5 5 S10 6 V ai( April 7, 1953 Patented Apr. 7, 1953DEVICE FOR STABILIZING AND HOMOG- ENIZING LIQUID MIXTURES Stig H. BjarneZachariassen, Stockholm, Sweden,

assignor to Aktiebolaget Separator, Stockholm, Sweden, a corporation ofSweden Original application May 12, 1949, Serial No. 92,774, now PatentNo. 2,595,376, dated May 6,

f 1952. Divided and this application October 30, 1951, Serial No.253,809. In Sweden May 14,

2 Claims.

. when they are passing'through the narrow slot,

that they are divided into a number of smaller particles. As the energynecessary for generating the requisite high pressure cannot berecovered, homogenizing machines of this type entail very high operatingcosts.

' Accordingly, a great number of other constructions, so-calledlow-pressure homogenizers, have been devised. The latter work upon verydifferent principles, the homogenizing being eifected by means ofpressures between 1 and 10 atmospheres. The power consumption of thesemachines is, of course, correspondingly smaller, but their homogenizingeifect largely corresponds to the operating pressure, so that they cangenerally be used only for comparatively simple problems. When highrequirements must be met in the homogenizing, these machines thereforecannot be used.

Y The homogenization of milk and cream presents a'dicult problem,because in this case an katomization of the fat globules to maximum 2.a,and preferably only 1li or less, is required. Heretofore, it hasbeenpossible to solve this problem only by meansv of high-pressurehomogenizers operated by pressures of at least 50 to 100 atmospheres.Homogenizing of milk therefore has not found the practical'v andextensive use which could have been expected.

I have found that it is possible to treat liquids to be homogenized (forexample, milk and cream) lby means of considerably lower pressures andyet obtain the same final quality of the product.V This is accomplishedby abandoning the principle on which the high-pressure homogenizers workand, instead, utilizing the available pressure for homogenizing in adevice constructed according to the present invention. This devicewords, is converted into a heating of the liquid.

By means of the cyclone, the liquid is forced into the whirl chamber notonly with a velocity along the axis of this chamber but also with arotative motion about the axis of the whirl chamber. The liquid ispreferably discharged from thecyclone into the whirl chamber by way ofan axial nozzle, the cyclone action causing the liquid to be more orless sprayed through the nozzle so that the particles penetrate into theliquid in the whirl chamber. L i

Tests have shown that by the use of the new stabilizing and homogenizingdevice, vaverage diameters of the fat globules ranging from 1.1 to 1.3Mcan be obtained, when working with pressures of only 12 to 25atmospheres in the homogenizer. On the other hand, with the besthighpressure homogenizers of known types, a pressure of to 100atmospheres would be required for the same purpose. By reason of thisfact alone, the device of the present invention is of great importancein practical operation because of the saving of power consumption whichit enables; but in addition, simple pumps, such as screw pumps,toothed-wheel pumps, and possibly multi-stage centrifugal pumps, maybeused as a source of pressure for the feeding means. Since these pumpshave a considerably higher efficiency than the piston pumps which haveto be used in the case o f pressures of 100 atmospheres and more, asaving of power consumption of to per cent is achieved. Furthermore, itis possible to dispense with the inlet and outlet valves whichcomplicate the use of high pressure homogenizers so that, takingeverything into account, a construction is obtained which, while havingthe same eiciency, requires only a fraction of the consumption ofmaterial and power of piston pumps and which, moreover, is considerablysimpler and can be kept clean and hygienic with less work.

As previously mentioned, the source of pressure for supplying the liquidto the cyclone may generally be a screw pump or possibly a toothed-Wheel or centrifugal pump. When particularly high requirements are putvon thev homogenized liquid and when, for some reason, the liquid mustalso be separated, the source of pressure may be the rotatingbowl of acentrifugal separaton'as disclosed in my copending applicationSerial No.

92,;7v4,'1ea May 12, 1949, now Patent No. 2,595,376, dated May 6, 1952,of which this application is a division.

For a better understanding of the invention,

' reference may be had to the accompanying drawing, in which:

Fig. 1 is a horizontal sectional view of a preferred form of the device,showing the whirl chamber and the cyclone; and

Fig. 2 iis a vertical sectional view on `.the Eline 2-2 in Fig. 1.

The liquid to be treated is fed to a cyclone I by way oi' its inlet 2.'Ihe cyclone has at one end a central, axial outlet 3 whichis preferablyin the form of a nozzle. The nozzle '3 discharges the liquid into acylindrical whirl chamber formed by a member 4, where the liquidvelocity is converted as far as possible ,into internal liquid friction.The liquid enters the whirl chamber 4 along its axis, 'and thehomogenized liquid is discharged from Vthe whirl chamber over the outletedge '5 thereof .at :the entrance end of this chamber. In order topermit adjustment of the distance of the whirl chamber 4 from the outlet3 of the cyclone, I prefer to arrange the latter so that it is movableaxially relative to `4the whirl chamber, fas by means :of the yslidingconnection lprovhied by fa -sleeve :E connected ito the whirl chamberand surrounding `and slidably :engaging the cyclone. The rsleeve 6"forms an :outlet 'l v:for the treated liquid.

It will be understood ithat the :cyclone vI imparts ia `rapid rotationto the liquid discharging through nozzle f3 yinto fthe whirl chamber14,'thus increasing the velocity gradient in chamber il. ((Thisrotational velocity eis `an taddition to the axial velocity fof theliquid Ypassing through 'the nozzle.) In the .device .as illustrated,the liquid leaves the whirl .cham-ber 4 fin a direction paralylel but:opposite to the linlet direction, which has the effect 'of 'producing a-high relative velocity between the incomingand the discharging`v:liquid l:in 'the whirl ichamber.

:By way .of 'further explanation, it is .to be noted that a high'homogenizing eiect requires a high velocity gradient. Aihigh velocitygradient, that is, a highvelocityxdifferencebetween two adljacent liquidlayers, :causes the femulgated droplets `of .the liquid mixture 'to betorn `into `smaller particles. In the whirl chamber d, the 'Velocitygradient of :the whirls produced vis proportional 'to the velocity `o'fthe in-'iiowing liquid, rand this '-velocityTi-nturn lis 'proportionalto the square root fof the lewailable pressure. 'In the .cyclone I, va

great velocity gra-'dient iis obtained in the :center (the velocitymultiplied Aby `the radius v'is "conetant), fand this 'velocity`gradient is fdirec'tly proportional to the available pressure,Consequently, thecyclone SI iis well adapted for homogfenization at theArelatively 'high `pressure at 'which thelliquidis forced Vthrough inlet2. The whirl chamber A, kon the other hand, v*works weil with asmallpressure Senergy. The liquidfisdis- .charged .from v.the :center.of cyclone I through the axial aperture 3, and vin order ito obtain v'ahigh velocity gradient .it .lis :advantageous :that the aperture 3 benot too large, 'thereby pro- .viding rsuiiicient `:pressure atodischarge the ,liquid through the ,outlet of the 'cyclone I with asubstantial axial velocity. The :whirl Y.chamber f4 has -a goodhomogenizing 4effect at `Va low velocity yof the liquid, and athis:chamber :is .arranged zbeyond the cyclone I in `order to utilize the.velocity of .the -liquidzdischarging ffrom the zcyclone. Thecombination ofi-the cyclone I` and -thewhirl 4 chamber 4 thus provides avery good homogenizing effect, because the ycyclone utilizes therelatively large `pressure .drop `and the whirl chamber the relativelysmall Ipressure drop.

The dimensions of the cyclone I and of the Whirl chamber 4 should beadapted to the liquid mixture to be treated and to the desiredthroughput rate. The dimensions of the cyclone may be easily calculated,since the flow of liquid and the pressure Vdrop in the cyclone followknown laws. With regard to the whirl chamber, it is a .general .rulelthat the higher the pressure for the desired eiect, the longer thewhirl chamber must be, yreckoned. in the axial direction of the liquid`jet issuing from the cyclone. The volume and the distance of the whirlchamber from the outlet of the .cyclone is also determined by theviscosity of the liquid to be treated. As an example, the following dataapply to a device for homogenizing mill; so that no cream plugs are4formed within 48 hours: pressure of l5-30 :kgs/cm2 in the -whirlchamber 4, diameter of whirl chamber 6-12 mms., length of whirl chamber-50-70 mms., distance between outlet 'edge Vii of whirlchamberand'outlet of nozzle 3 :greater .thane mms. if, for example, 12 vpercentcream is .homogenized by means of a higher pressure, the aforesaiddistance :should be greater, possibly as much as 20 mm.

I claim:

l. A device for .stabilizing and .homogenizing liquid mixtures, which'comprises a ycyclone having an inlet for the mixture, the cyclone alsohaving a central outlet `for the mixture, and a member forming a vwhirlchamber positioned to receive the mixture discharged :through saidoutlet and in which the zvelocity oi Athe vmixture is .converted atleast largely ,into internal liquid friction, the `whirl chamberA'having an open end adjacent said `central Aoutlet and .being `closedat the opposite end, ,said central :outlet 'being positioned `todischarge the lmixture into the central part of said open end and'toward :the closed end, the edge of .the whirl chamber `at its open:end forming an outlet for discharging the treated mixture from 'theVWhirl chamber.

2. .A vdevice for stabilizing fand .homogenizing vliquid mixtures, whichcomprises a cyclone havling Yan :inlet for the imixture, the .cyclone-also having a central outlet for the mixture, -a member forming `awhirl chamber :positioned to vreceive 4the `mixture discharged throughsaid Ioutlet and. in which the Avelocity of the :mixture is converted4at least largely into internal liquid friction, .and va slidingconnection 'between the `cyclone and said lmember forming .the whirlchamber, whereby the vdistance of the Awhirl chamber from-said centraloutlet :may be varied.

'STIG I-I. BJARNE ZA'CHARIASSEN REFERENCES CITED The followingreferences are of 'record in the iile of this Vpatent:

FOREIGN .PATENTS .France .June A1Q, .51922

